"Roy Lewallen" wrote in message
...
Owen Duffy wrote:

Beware of having 50 and 75 ohm versions of BNC and like around,
incorrect pairing risk damage to the female connector. Most 75 ohms
applications still use 50 ohm BNC connectors, even though 75 ohm
versions are available.

I keep reading this, and it puzzles me. I have a number of RG-59 patch
cables which have 75 ohm BNC connectors fitted (and others with 50 ohm
connectors). As far as I can tell with a magnified inspection, the center
conductor of the 75 ohm male BNC is the same diameter as it is in a
standard 50 ohm BNC. The only apparent difference is that the dielectric
around the inside of the outer mating area is much thinner in the 75 ohm
connector, and the diameter of the 50 ohm center pin steps up as it enters
the solid dielectric at the bottom while the 75 ohm center pin doesn't.

Since the pin of the male connector is wholly inserted into the socket, its
diameter should not matter. The OD of the *female* center conductor should
be different. Also, the OD of the back end of the male connector (the part
that does not insert) should be different. There were dimensions available
at the Tyco web site.

Tam/WB2TT